Ask question

Ask question

All categories

3 years ago

8

A book is thrown downward from the library window with a speed of 2.0 s m and lands on the ground 5.0 m. We can ignore air resis

tance. What is the final velocity of the book in m/s?

2 answers:

OlgaM077 [116]3 years ago

6 0

Answer:

<h3>10.1m/s</h3>

Explanation:

Using the equation of motion v² = u²+2as where;

v is the final velocity

u is the initial velocity

a is the acceleration due to gravity

s is the height of fall

Given

u = 2.0m/s

s = 5.0m

g = 9.81m/s²

Required

final velocity of the book in m/s

Substitute the given parameters into the formula;

v² = u²+2as

v² = 2²+2(9.81)(5)

v² = 4+98.1

v² = 102.1

v = √102.1

v = 10.1m/s

<em>Hence the final velocity of the book in m/s is 10.1m/s</em>

Pie3 years ago

3 0

Answer:

-10

Explanation:

I got that mf right

You might be interested in

A contestants spin a wheel when it is their turn in a game show. One contestant gives the wheel an initial angular speed of 3.40

guajiro [1.7K]

Answer:

4.62 s

Explanation:

We are given that

Initial angular speed, $\omega=3.4 rad/s$

$\theta=1\frac{1}{4} rev=\frac{5}{4}\times 2\pi=2.5\pi rad$

$\omega'=0$

$\omega'^2-\omega^2=2\alpha \theta$

Substitute the values

$0-(3.4)^2=2\times 2.5\pi \alpha$

$\alpha=\frac{-(3.4)^2}{2\times 2.5\pi}=-0.736 rad/s^2$

$\omega'=\omega+\alpha t$

$0=3.4-0.736 t$

$-0.736t=-3.4$

$t=\frac{-3.4}{-0.736}=4.62 s$

Hence, the wheel takes 4.62 s to come to rest.

3 0

4 years ago

A person holds a portable fire extinguisher that ejects 1.0kg of water per second horizontally at a speed of 6.0 m/s. What newto

Leviafan [203]

Answer:

6 N

Explanation:

$\dfrac{m}{t}$ = Mass flow rate = 1 kg/s

v = Final velocity = 6 m/s

u = Initial velocity = 0 m/s

Force is obtained when we divide change in momentum by time

$F=\dfrac{m(v-u)}{t}\\\Rightarrow F=\dfrac{m}{t}(v-u)\\\Rightarrow F=1(6-0)\\\Rightarrow F=6\ N$

The force the person exert on the extinguisher in order to prevent it from accelerating is 6 N

7 0

3 years ago

The distance between Pluto and the Sun is 39.1 times more than the distance between the Sun and Earth. Calculate the time taken

german

Answer:

Explanation:

Given

Distance between Pluto and sun is 39.1 times more than the distance between earth and sun

According to Kepler's Law

$T^2=kR^3$

where k=constant

T=time period

R=Radius of orbit

Suppose $R_1$ is the radius of orbit of earth and sun

so Distance between Pluto and sun is $R_2=39.1\cdot R_1$

$T_1$ and $T_2$ is the time period corresponding to $R_1$ and R_2[/tex]

$(T_1)^2=k(R_1)^3---1$

$(T_2)^2=k(R_2)^3---2$

divide 1 and 2

$(\frac{365}{T_2})^2=(\frac{R_1}{39.1})^3$

$T_2^2=365^2\times 39.1^3$

$T_2=89239.67\ Earth\ days$

7 0

3 years ago

Which of the followijg is an example of kinetic energy

Ipatiy [6.2K]

Answer:

D

Explanation:

D. A swing moving back and forth

3 0

3 years ago

Read 2 more answers

The cost of energy delivered to residences by electrical transmission varies from $0.070/kWh to $0.258/kWh throughout the United

tankabanditka [31]

Answer:

(a) $ 1.48

(b) $ 0.005

(c) $ 0.38

Explanation:

(a)

First, we calculate the energy consumed, by using following formula:

E = Pt

where,

E = Energy Consumed = ?

P = Power Delivered = (40 W)(1 KW/1000 W) = 0.04 KW

t = Time Duration = (2 weeks)(7 days/week)(24 h/day) = 336 h

Therefore,

E = (0.04 KW)(336 h) = 13.44 KWh

Now, we calculate cost, by following formula:

Cost = (E)(Unit Price)

Cost = (13.44 KWh)($ 0.11/KWh)

<u>Cost = $ 1.48</u>

<u></u>

(b)

First, we calculate the energy consumed, by using following formula:

E = Pt

where,

E = Energy Consumed = ?

P = Power Delivered = (970 W)(1 KW/1000 W) = 0.97 KW

t = Time Duration = (3 min)(1 h/60 min) = 0.05 h

Therefore,

E = (0.97 KW)(0.05 h) = 0.0485 KWh

Now, we calculate cost, by following formula:

Cost = (E)(Unit Price)

Cost = (0.0485 KWh)($ 0.11/KWh)

<u>Cost = $ 0.005</u>

<u></u>

(c)

First, we calculate the energy consumed, by using following formula:

E = Pt

where,

E = Energy Consumed = ?

P = Power Delivered = (5.203 x 10³ W)(1 KW/1000 W) = 5.203 KW

t = Time Duration = (40 min)(1 h/60 min) = 0.67 h

Therefore,

E = (5.203 KW)(0.67 h) = 3.47 KWh

Now, we calculate cost, by following formula:

Cost = (E)(Unit Price)

Cost = (3.47 KWh)($ 0.11/KWh)

<u>Cost = $ 0.38</u>

8 0

3 years ago